Brown spotting after intercourse

Good morning glow members. My question is I've had three days of spotting after my husband and I had sex(on my ovulation peak day). However I am on birth control and have been slacking on taking them at the same time every day for the past week and skipped some as well. Is this something I should be concerned about? It is not a significant amount and I am not cramping but I am having some lower back pain. My period is less than 2 weeks away.